Authenticity of Ancient Artifacts Indicated by Environmental Dust

Dust is a significant, albeit under-recognized, component of patinas that accumulate on exposed surfaces of artifacts. Dust storms are ubiquitous in the Levant, often containing minerals, microfossils, and pollen which can be found within the patina of an artifact, preserving its geological signature. Archaeological materials that are exposed to local environmental and depositional processes in a tel, a cave, or soil, may accrete in a patina over time and may have some dust components reflective of the environmental record. Modern anthropogenic aerosol sources are often characterized by the presence of heavy metals. Pollen from fruits and shrubs that is not indigenous, if found in the patina, can be used to differentiate recent artifacts from those of antiquity. The scores of unprovenanced looted antiquities have necessitated the need to differentiate a genuine artifact from a modern fraud. Since the geological component of the dust in the Levant is known, and the climate and its attendant wind patterns apparently were quite constant during recent millennia times, the dust in the patinas of a true artifact is easy to differentiate from patinas containing modern dust. Both contemporary and historical dust can serve as tools to authenticate an artifact. The well-known unprovenanced, Jehoash inscription tablet, the James ossuary, and the inscribed ivory pomegranate preserved in their patinas microfossils and particles reflective of the geological environmental dust which strengthens the contention that their inscriptions are authentic.

The
ability to authenticate archaeological artifacts is of critical
importance. If the exact provenance of an archaeological artifact is
not certifiably obtained from an official excavation, its
authenticity may be suspect. Thus, archaeologists are at times
confronted between choosing to limit their data base to only material
exclusively obtained from an official excavation and widening their
historical sources by including artifacts that have the potential of
being historically significant but are not well provenanced. A
notable example of the latter would be the Dead Sea Scrolls. Many of
the ancient sites in the Middle East have been extensively looted.
Many artifacts are unprovenanced and are

found in
private collections and even in museums (e.g., the Amarna Letters
from Egypt are now exhibited by many museums worldwide). The problem
then is how to differentiate a genuine artifact
from a modern fraud. One archaeometric method would be to study the
patina that has accreted on the surface of the artifact over time.
This, of course, presupposes that one knows whatto expect
in the patina for validation. We wish to discuss components that
should be contained in genuine patinas of archaeological artifacts
from arid or semi-arid lands or, conversely, what may be contained or
lacking in modern forgeries. Previous work in this field has been
sparse. Ayalon et al. (2004) Goren (et al., 2004, 2005) and Ilani et
al. (2002, 2008) have studied the patina of unprovenanced artifacts.

As modern
Israel and the historical Holy Land, including the Sinai Peninsula,
are generally dry and dusty, wind-blown dust should be a ubiquitous
component incorporated into accreting patinas, both historical and
modern. In this study, we summarize results based on years of
sampling and investigating modern atmospheric dust from various
regions of Israel and Sinai that contribute components to the total
atmospheric dust budget. The regional dust may be useful in readily
differentiating genuine artifacts whereas the local contribution of
dust particles can aid in determining provenance on a finer scale.
Some of the components of modern dust should be similar to past
components, whereas others are restricted to modern times and thus
should not be present within the patina of authentic archaeological
artifacts.

MATERIALS
AND METHODS

Over the
course of this study,
dust was collected from 27 sites in Israel and Sinai (Fig.1; Ganor et
al., 2007, 2009). Atmospheric, transported, and precipitated dust
were collected: (A)
at ground level, (B) by collectors on the roof of the
Department of Geophysics and Planetary sciences
of Tel Aviv University , and (C)at
a height of 850 m via airborne collectors. Our dust sampling in
Israel and Sinai (Ganor et al., 2009, Fig. 1) has been systematic and
was collected every month for five years (Ganor, 1975). The methods
of collection and methods of study including the travel paths and
points of origin of the dust brought to Israel, the meteorological
conditions and the sedimentation processes are described and
discussed (Ganor et al., 1975; Ganor et al. 1991, 1995; Ganor et al.,
2009; Yaalon and Ganor, 1979).

RESULTS

Natural
Aerosols

There are
three types of aerosols present today in the atmosphere over the
region. Two of these, desert and marine, are natural; the third type
is of modern anthropogenic aerosols. Regional wind-blown dust finds
its source in the deserts of Libya, Egypt, Sinai, westward (Yaalon
and Ganor, 1979) and to a much lesser extent in Saudi Arabia (Ganor
et al., 1991). The mineral composition of the dust from both regions
is similar, except for the clay mineral composition.The
dust is composed of mineral grains including quartz, calcite,
dolomite, feldspar, halite, gypsum, and clay minerals (Ganor et al.,
2009, Fig. 2A-D). The feldspar content is generally small,
comprising approximately 3 to 5 %. However,
locally where basalts
are exposed, such as along the Rift Valley (Lake Kinneret, Golan, and
Dead Sea stations; Ganor et al., 2009, Fig. 1) the amount of feldspar
increases and can become the dominant mineral component (Ganor et
al., 1991). Locally, apatite (1 to 5%) has been recovered from
dust
over the Negev Desert (Singer et al., 2003). Phosphate has been found
in dust in the vicinity of Haifa as a minor component (Ganor et al.,
1998), thederivation
of which is most probably from a local phosphor-gypsum plant, and in
the central Negev from exposures of phosphate formations and
industrial plants (Singer et al., 2003). These two desert-derived
dust sources are similar in composition (enriched with calcium,
chlorine, sulfur and phosphate), grain size, morphology, and
mineralogy (Ganor, 1975; Ganor et al., 1991). The primary Saharan
Desert source contains a clay mineral mixture composed of kaolinite,
illite, smectite and mixed-layer
clays whereas the dust derived from the deserts to the south (Saudi
Arabia) is composed of palygorskite, kaolinite,
and some mica (Yaalon and Ganor, 1979). Natural dusts have beneficial
affects upon the soils, enriching them in nutrients such as K, P, S,
NH4
and
organic material (Herut and Krom, 1996). Marine
aerosols derived from Mediterranean Sea spray constitute up to 3 % of
the dust composition (Ganor, 1975). As these are generally soluble
salts such as halite,
they
would tend not to be preserved within a patina.

Modern
industrial-related aerosols

Modern
anthropogenic aerosols (the third type) such as fly ash are being
released from power plants,
vehicle exhaust, industrial plants, (Ganor et al., 2009, Fig. 2E,H
and I) agricultural emissions, and heating units (Levin and
Lindberg, 1979). Urban dusts have been studied for their chemical
composition in Tel-Aviv (Donagi et al., 1979); Jerusalem (Malenky et
al., 1983) and Beersheva (Kushekevsky et al., 1983). The
anthropogenic component is often characterized by the presence of
potential biologically active heavy metals, particularly lead,
vanadium, nickel, chromium, copper, and zinc. Ganor et al. (1991)
found that modern aerosols are generally richer in lead and brome due
to the use of leaded gasoline, which is now being eliminated in
commercial gasoline. Vanadium and nickel are elemental components of
the heavy fraction of fuel oil used in petroleum-based power plants
(Ganor et al., 1998) located in Tel Aviv and Haifa, and are chemical
characteristics of aerosols that they emit. The Ashdod and Hadera
power stations are coal-based.

In
Biblical times the majority of particles settling on the ground and
other surfaces were natural particles identified as carbonate,
quartz, clay, and some feldspar. In recent centuries, however,
industry has contributed a significant amount of anthropogenic
contamination. These man-made particles can be used to distinguish
authentic ancient artifacts from attempted modern forgeries. Fibrous
particles in general are characteristic of anthropogenic contaminants
introduced in modern times through industrial processes. Examples of
industrial particles are asbestos fibers that detach from the
asbestos cement blocks widely used in building since 1952 (Ganor et
al., 2009, Fig. 2F). Other fibrous materials include basalt, glass,
and carbon fibers, all of which are used as insulating materials and
represent recent particulates introduced into the atmosphere as dust.
Basalt is used in the Kingdom of Jordan as raw material for the
industrial production of fibrous rock-wool. Clumps of small metals
spheres composed of iron and copper, along with a variety of
ancillary heavy metals, are modern contaminants arising from welding
and the metallurgical industry.

The
introduction of coal power stations has resulted in the release of
fine particles of coal and fly ash. These dust particles are
identifiable by their spherical shape and small size (generally <1
μm; Ganor et al., 2009, Figs. 2H and I). Black particles of soot
released from oil-based
power plants contain carbon, nickel, vanadium, zinc, titanium and
copper. With the upsurge in construction, the buildingindustry
resorted to fabricating white bricks made of pumice, amorphous
silica,
and tobermorite called Autoclaved Aerated Concrete (AAC). Aerosols
resulting from the abrasion of these materials also contribute to the
make-up of modern dust.Fine-grained
particles of poorly defined morphology but rich in carbon, lead, and
brome originate from the exhaust fumes of diesel and gasoline powered
vehicles (Ganor et al., 2009, Fig. 2F). These represent modern
contributions to airborne dust especially over urban areas. Gunpowder
residue identified by its morphology, size (1-2 μm), and three
typical elements, namely, antimony, barium, and lead, is likewise a
relatively modern contribution to the composition of ambient dust.

Pollen

Modern
dust over Israel contains pollen particles and spores from
agriculture and
the
ornamental flower industry. Monitoring of the range of pollen
particles has been carried out in Jerusalem and Tel-Aviv (Horowitz et
al., 1975). In the arboreal fraction of modern pollen five tree types
are overwhelmingly dominant: Quercus
spp., Olea
europaea
(Ganor et al., 2009, Fig. 2J), Eucalyptus
spp.,
Cupressus
sempervirens and
Pinus
halepensis.
The other contributors occur infrequently and sporadically in minor
amounts. All of the pollen observed and collected represents plants
growing within Israel and the adjacent regions today. One exception
is the Eucalyptus
spp.
for
it is clearly not indigenous, being a modern import from Australia
since the late 1800s. Likewise, pollen from fruits and shrubs that
have been recently introduced can be used to differentiate recent
from ancient artifacts. For example, the tomato, potato, egg plant
and corn, all dietary staples today, are post-Columbus,
coming from the Americas. Even the Sabra cactus was introduced from
the Americas. Likewise, the common yellow flowering wild mustard
(Eruca
sativa)
is believed to have been introduced into the region by the Crusaders.
There are other non-indigenous plants that can contribute to the
local pollen spectrum and their presence within a patina offers
another potential key for use in authenticating and dating an
artifact.

Calcareous
microfossils

Calcareous
microfossils and nannoplankton, primarily foraminifera and
coccolithophorids, are other elements that are commonly found in
airborne dust (Ganor et. al., 2009, Fig. 3A-J). At El-Arish, in
northern Sinai, fragments of modern land snail shells are a
characteristic fraction within the regional dust components (Ganor,
1975). The microfossils found in the trapped dust range in age from
Cretaceous (145.5 - 65.5 million years) to Palaeogene (65.5-23
million years). Thus,
they
are similar in age to the marine carbonate rocks that are widely
exposed over most of Israel. The microfossils were studied from dust
collected from Haifa, Jerusalem, and Tel-Aviv by Dr. Shimon
Moshkovitz (personal communication) of the Geological Survey of
Israel (Table 1, Ganor et al., 2009) and are extremely
well-preserved, generally with intact tests (shells). The fact that
the foraminiferal chambers are empty enables them to easily become
airborne (Ganor et al., 2009, Fig. 3, C, D). These microfossils
should be as plentiful in the historical past as they are today.
These marine carbonate microfossils were indeed found within the patinas
of the Jehoash inscription,
the James ossuary, and the ivory pomegranate may be an indication of their authenticity.
Microfossils can be used to provenance inorganic artifacts (Quinn, 2008) and their
absence within a patina purportedly coming from the Jerusalem area
would be suspicious since the entire city is situated upon marine
Cretaceous carbonates.

Accumulation
rates

The
annual amount of
atmospheric
dust that settles out over Israel decreases from south to north,
averaging 200 tons/km2to
30 tons/km2,
respectively
(Ganor and Mamane, 1982). During dust storms the amount of dust that
settles out over Jerusalem, situated on the desert boundary, ranges
from 0.1 to 1.1 g/m2/hr,
a significant amount. The thickness of
loess that has accumulated
in Beer Sheva Valley since the start of the Quaternary is calculated
at 13.5 m (Yaalon and Ganor, 1979). The dust that is removed from the
atmosphere during rainfall is different in size distribution from the
material of dry dust storms. During dust storms, the sediment that is
deposited exhibits a bimodal grain size distribution. One mode
represents <20-60 μm silt and the other <2 μm clay.Rainfall
deposits smaller-sized material in a unimodal distribution. The
clay-sized component of rain is 50%-65%, compared to only 10-20% from
dry deposition. Clay is often attached to the larger silt-sized
particles; however, not all clay-size particles are clay minerals.

DISCUSSION

Dust is
an important component of soils in a tel (artificial mound)
environment and was ubiquitous at ancient sites in the Holy Land.
Patinas that developed on artifacts over many years accreted elements
from the surroundings that existed within those dust-rich soils. The
wind patterns apparently were similar during the last millennia in
Israel and Sinai (Enzel et al., 2007). Thus the dust contained in
patinas of true artifacts can be differentiated from patinas
containing modern dust contributions. The analysis of dust components
in a patina will assist in validating an artifact’s antiquity
whose authenticity may have been called into question.

The microfossils
derived from the weathering of the Cretaceous
to Palaeogene
exposed rocks are deposited by wind. Indeed well-preserved marine
carbonate microfossils, such as Cretaceous to Eocene foraminifera and
nannoplankton, occur in abundance in everyday dust in Jerusalem
(Ehrenberg, 1860; Ganor, 1975
Ganor, et al. 2007,
2009) as well as in the local soils.

During
the past several years at least three artifacts of historical
importance have been labeled modern forgeries because it was
contended that their patinas contained alien material. It should be
pointed out that in all three cases a principal argument against
authenticity of artifacts from Jerusalem was the presence of marine
microfossils within their patinas. An example of this problem can be
found in the study of the patina of the tablet with the inscription
referring to King Jehoash (Ilani et al., 2002, 2008). Though, its
provenance is not readily verifiable, its historical significance is
potentially of tremendous importance

.One
of the arguments that had been used against its authenticity was the
finding of Cretaceous-age foraminifera in the patina (Goren et al.,
2004). Likewise, the presence of marine nannoplankton (specifically
coccolithophorids) of Cretaceous age incorporated into the patina of
the ossuary that was related to James with
the inscription “Yaakov Son of Yosef Brother of Jesus”
also
from the Jerusalem area, was likewise construed as proof
(among other arguments) ofits
being a modern fraud (Ayalon et al., 2004), though these artifacts
lack any representatives of modern dust contaminants within their
patinas. In the third example, an inscribed ivory artifact in the
shape of a pomegranate was also considered to be a fake becauseit
too contained Cretaceous marine nannoplankton within its patina
(Goren et al., 2005). Other epigraphical and archaeometric
considerations that strengthen the pomegranate authenticity are
discussed in Lemaire (2006) and Rosenfeld and Ilani, (2006). Yet, as
has been noted, these Cretaceous foraminifera and coccolithophorids
are natural components particular to, and common in Jerusalem dust;
both today’s dust as well as dust from the historical past.
Their presence in the patina is entirely natural, coming from the
physical erosion of the extensive natural exposures of Cretaceous
marine limestones and chalks. Indeed, their absence, on the other
hand, within an accreted patina from Jerusalem, should be construed
as suspicious. Modern contaminants, as mentioned above, have not been
encountered within the
patinas of these three artifacts.

Other
particles that were found preserved in the ancient patina of the
Jehoash Inscription tablet are carbon ash and gold globules
associated with burning. These carbon ash particles dated by
radiocarbon to 2250 +- 40 years BP may indicate the authenticity of
this unprovenanced artifact

The components of dust are related to the geological and floral
environment. The dust from that environment can be trapped and
preserved within the patina of an artifact, preserving its geological
and time signature. Dust, which is ubiquitous in the Levant, can be
implanted and preserved within an accreting patina. Modern-day dusts
in urban as well as agricultural regions within Israel differ in
composition from their historical counterparts. Ambient dust from
other geographical regions contains characteristic components that
can be used to reveal the area of origin. Archaeological materials as
well as blatant forgeries are all exposed to the local environment,
be it that of a tel, a cave, soils, or the ambient air of a
laboratory. The dust in the patina of an ancient artifact and that of
a forgery may be significantly different, especially if the forgery
was carried out in a geographical region different from the one that
it purports to represent. Therefore, it is proposed that when the
validity of potentially important artifacts is called into question,
the dust preserved in the accrued surface patina be studied along
with the other ancillary methods (within the inner layer
of the patina) in the process of archaeological authentication.
Additional research is needed to determine
how widely an analysis of dust in patinas might be of use,
geographically or temporally. We do not see any limitation to this
technique other than that there is no ambient dust in a particular
region; however, this is not a problem in the Middle East. One
potential problem is misidentification of the inclusions, whether
they are fossils or anthropogenic particles.
Although the debate on the authenticity of the Jehoash
inscription tablet, the James ossuary, and the ivory pomegranate is
ongoing at present, the natural dust components occurring within
their patinas are good examples to illustrate how the examination of
included dust can help clarify and validate artifact authenticity.